The present invention relates to the novel isobutyl and n-hexyl esters of 2-methyl-4-pentenoic acid and compositions and processes using such 2-methyl-4-pentenoic acid and esters to alter the flavor of foodstuffs, chewing gums and medicinal products.
There has been considerable work performed related to substances which can be used to impart (or enhance) flavors to (or in) various types of foodstuffs, chewing gums and medicinal products. These substances are used to diminish the use of natural materials, some of which may be in short supply and to provide more uniform properties in the finished product. Sweet, fruity, strawberry, pineapple-like, pear and green aromas as well as tastes are particularly desirable for many uses in foodstuff flavors.
U.S. Pat. 3,499,769 issued on Mar. 10, 1970 discloses processes for imparting a fresh fruity flavor (particularly strawberry flavor) to foods by adding a small amount of 2-methyl-4-pentenoic acid to the foodstuff. In U.S. Pat. 3,499,769 it is emphasized that the basic nuance imparted by the 2-methyl-2-pentenoic acid is a "berry" flavor.
Quite unexpectedly, the 2-methyl-4-pentenoic acid and esters thereof of the instant invention have properties different in kind from the 2-methyl-2-pentenoic acid of U.S. Pat. 3,499,769 which is only fruity and strawberry-like and does not have the sweet, fruity, pineapple-like, pear and green aroma and taste qualities of the 2-methyl-4-pentenoic acid esters of the instant invention.
Arctander, "Perfume and Flavor Chemicals", 1969, discloses the use in perfume compositions and flavors of 4-pentenoic acid, thus:
"... only rarely used in perfume compositions mainly on fruity bases and certain artificial essential oils. PA1 It finds use in flavors on account of its sour-caramellic taste, pleasant at levels below 10 ppm, and including an almost sweet aftertaste. Higher concentrations have acrid taste and repulsively acid odor, pungent and irritating. PA1 Traces, equivalent to 1 to 5 ppm, are used in imitation butter flavor and in various fruit flavor complexes, e.g., apple, pineapple, apricot and strawberry." PA1 "Spicy-rooty, sweet-sour herbaceous odor of moderate tenacity." PA1 p-Hydroxybenzylacetone; PA1 Geraniol; PA1 Maltol; PA1 Ethyl methyl phenyl glycidate; PA1 Benzyl acetate; PA1 Vanillin; PA1 Methyl cinnamate; PA1 Ethyl pelargonate; PA1 Methyl anthranilate; PA1 Isoamyl acetate; PA1 Alpha ionone; PA1 Ethyl butyrate; PA1 Gamma-undecalactone; PA1 Naphthyl ethyl ether; PA1 Diacetyl; PA1 Ethyl acetate; PA1 Anethole; PA1 Isoamyl butyrate; PA1 Cis-3-hexenol-1; PA1 2-Methyl-2-pentenoic acid; PA1 Elemecine (4-allyl-1,2,6-trimethoxy benzene); PA1 Isoelemecine (4-propenyl-1,2,6-trimethoxy benzene)
At Vol. II, No. 2452. Arctander also discloses the use of trans-2-methyl-2-butenoic acid (tiglic acid) at Vol. II, No. 2949 in perfumery:
And the use of cis-2-methyl-2-butenoic acid (angelic acid) and alkyl esters thereof in perfumes and flavors at Vol. I, No. 238.
The alkenoic acids and esters thereof of the prior art are considered to be different in kind from the 2-methyl-4-pentenoic acid esters of the instant invention insofar as the organoleptic properties are concerned.
Rossi and Ingrosse, Chem.Abstr. 69, 95851(g) (Abstract of Gazz.Chim.Ital. 98(7), 866-83 (1968)) discloses the preparation of 2-methyl-4-pentenoic acid by reacting 3-chlor-propene-1 with 1,1-dicarboethoxyethane.
De Moura Campos and de Amarat, Chem.Abstr. 63: 4159(e) (Abstract of J.Arch.Pharm. 298(2), 92-100 (1965) discloses the preparation of 2-methyl-4-pentenoic acid by the following reaction sequence: ##SPC1##
Trace and Gurante, Chem.Abstr. 55:14324(i) (Abstract of Rend.Inst.Lombardo Sci. Pt.I, Classe Sci. Mat. e Nat., 94A, 309-330 (1960) discloses a process for preparing 2-methyl-4-pentenoic acid by reacting 2-cyclopropyl-propionic acid with HBr.
Adler and Brachel Chem.Abstr. 57: 2042(d) (Abstract of Ann. 651, 141-53 (1962) sets forth a process for giving 12% yields of methyl-2-methyl-4-pentenoate by means of the following reaction: ##SPC2##
These processes as well as other processes of the prior art do not suggest the unique compounds of our invention.